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This invention relates to a device or an apparatus for cleaning cylindrical air filters that are used in trucks, heavy equipment or similar types of machinery including filters that are used in other environments. U.S. Pat. No. 4,808,234 describes an apparatus attempting to overcome the disadvantages of cleaning filters by using liquid solvents or by using a xe2x80x9cdryxe2x80x9d cleaning air system wherein dirt, debris and other contaminants are dislodged from a filter and are then collected by a vacuum or other suction device. In this patent, air is supplied simultaneously to the inside and the outside surfaces of the cylindrical surfaces of the filter to dislodge dirt from the surfaces. Suction collects this dislodged dirt. As the air pressure is applied, the filter is rotated horizontally about its longitudinal axis. There is no way that any dirt can be collected from the inside surface of the cylindrical filter. Furthermore in U.S. Pat. No. 4,808,234, the operator must manually reach into the cabinet of the apparatus and hold the filter while securing it to a spindle. This is awkward and hazardous. In the invention at hand, there are certain safety precautions built into the machine which will be described below.
In U.S. Pat. No. 5,143,529 discloses a filter cleaning apparatus wherein the air filter to be cleaned is mounted in an upright position in a cabinet. High pressure and opposing air nozzles are mounted for vertical movements along the inner and outer surfaces of the filter to dislodge debris therefrom. Similarly, inner and outer vacuum nozzles are mounted adjacent to and moveable with the air nozzles for suctioning off the dislodged debris. Although this apparatus facilitates handling and mounting of the filter to be cleaned on both the inside and outside surfaces, it also involves some disadvantages in that the upright filter rotates during the cleaning cycle whereby centrifugal forces may cause the dirt to be tightly pushed into the bottoms of the pleated filter which makes the cleaning of the inside surfaces more difficult. The cleaning process is also more complicated because the dirt and debris on the interior of the filter may fall from the paper filter and much of it may into the corners of the filter, which is inaccessible to the force of the vacuum. Therefore, the filter is not completely cleaned.
U.S. Pat. No. 5,584,900 includes pneumatic hammer actions to aid in dislodging dirt. In this Patent, the filter is initially mounted into the apparatus in a vertical position and thereafter is moved automatically into a horizontal position. Thereafter a carriage moves air nozzles into the interior of the rotating filter while being supported on a roller bearing which is in touch with the surface of the filter.
U.S. Pat. No. 5,915,439 discloses an apparatus for cleaning filters. The apparatus is capable by adjustments to clean filters that are contaminated on both on the inside or outside surfaces. This apparatus also includes hammer actions to aid in the dislodging of debris.
The apparatus of this invention is especially designed to handle extremely long filters with narrow diameters, commonly referred as pleated bag filters or pleated bag replacements for the original fabric sock filter bag, which until now could not be cleaned on the above identified patented machines. These filters are used in an entire different environment other than air breathing internal combustion engines. The above mentioned filters are open at both ends and the filtering action can go both ways such as from the inside out or from the outside in depending on the machinery from which the filter was taken and how it was designed. The proposed apparatus of the inventive concept is designed and constructed to handle filters from 1 to 8 feet in length having an outside diameter of approximately 5xe2x80x3 to 6xe2x80x3 and inside diameter of approximately 3xe2x80x3 to 4xe2x80x3. It should also be noted that the filters that are subject to be cleaned are closed at one end. This is so because theses filters are used in bag houses or dust rooms in various plants where there is a high incidence of environmental dust. These bag houses use a multiple of filters that are hanging from the manifolds above and with the closed ends at the bottom. Prior art devices used filter bags made out of cloth and the whole assembly had to be shaken at certain intervals to dislodge the accumulated dirt or dust. The present filters are made of pleated paper whereby they offer a much larger circumferential surface to the dirty air streaming against its outer pleated surface, whereby the outer surface will be contaminated. In order to clean these types of filters, the inventive cleaning apparatus has be somewhat differently constructed than the prior art devices discussed above.
The filters to be cleaned are held in a horizontal position with a slight clamping pressure at both ends. The clamp itself utilizes a xe2x80x9ccapxe2x80x9d and xe2x80x9cconexe2x80x9d configuration to center the filter and to accommodate the same to their various end cap configuration. The clamp for the closed end of the filter (the xe2x80x9ccupxe2x80x9d) is manually adjustable for the basic length of differently sized filters with the actual clamping being done by short stroke pneumatic cylinders. The other end of the clamp that holds the open end of the filter (the xe2x80x9cconexe2x80x9d) is rotationally mounted at one end of the cleaning chamber.
The clamp at the closed end of the filter is able to rotate freely, and the other clamp end has a direct electric motor driven gear drive to rotate the filter. This cone end will also have a passage there through to enable compressed air to be delivered into the interior of the filter during the cleaning operation as will be explained below
To accommodate filters from different applications and from different environments, and with different substances thereon, the apparatus is able to rotate the filter incrementally through an adjustable number of degrees of rotation to concentrate the cleaning action on one narrow surface of the media at any one time, or to rotate the filter continuously for a random cleaning pattern.
The compressed air nozzles are moved laterally back and forth along the length of the filter using a roller bearing style linear guide system and a direct electric motor driven rack and pinion drive.
The length of travel for the nozzles is defined by a first and fixed limit switch at the turn table end of the cleaning chamber and another or second limit switch is triggered by the movable part of the clamp.
Both the turntable motor for rotating the filter and the nozzle motor for the lengthwise travel for the nozzle are located outside of the cleaning chamber to avoid any kind of contamination of the motors from the cleaning environment in the cleaning chamber.